To develop 1) a registry of hospital patients with neurologic disease in a well-defined population of 3.5 million people, 2) resources for case-control studies of neurologic diseases using uniform methods of data collection, 3) to develop a registry of neurologic disease in the well-defined population of the United States military, and 4) a registry of selected neurologic diseases in a well-defined population of 0.5 million people in a county in Hungary.